Baley looked at his watch with something approaching detachment. It was 21:45. In two and a quarter hours it would be midnight. He had been awake since before six and had been under tension now for two and a half days. A vague sense of unreality pervaded everything.

He kept his voice painfully steady as he reached for his pipe and for the little bag that held his precious crumbs of tobacco. He said, "What's it all about, Daneel?"

R. Daneel said, "Do you not understand? Is it not obvious?"

Baley said, patiently, "I do not understand. It is not obvious."

"We are here," said the robot, "and by we, I mean our people at Spacetown, to break the shell surrounding Earth and force its people into new expansion and colonization."

"I know that. Please don't labor the point."

"I must, since it is the essential one. If we were anxious to exact punishment for the murder of Dr. Sarton, it was not that in doing so we expected to bring Dr. Sarton back to life, you understand; it was only that failure to do so would strengthen the position of our home planet politicians who are against the very idea of Spacetown."

"But now," said Baley, with sudden violence, "you say you're getting ready to go home of your own accord. Why? In heaven's name, why? The answer to the Sarton case is close. It must be close or they wouldn't be trying so hard to blast me out of the investigation. I have a feeling I have all the facts I need to work out the answer. It must be in here somewhere." He knuckled his temple wildly. "A sentence might bring it out. A word."

He clenched his eyes fiercely shut, as though the quivering opaque jelly of the last sixty hours were indeed on the point of clarifying and becoming transparent. But it did not. It did not.

Baley drew a shuddering breath and felt ashamed. He was making a weak spectacle of himself before a cold and unimpressed machine that could only stare at him silently.

He said harshly, "Well, never mind that. Why are the Spacers breaking off?"

The robot said, "Our project is concluded. We are satisfied that Earth will colonize."

"You've switched to optimism then?" The plain-clothes man drew in his first calming puff of tobacco smoke and felt his grip upon his own emotions grow firmer.

"I have. For a long time now, we of Spacetown have tried to change Earth by changing its economy. We have tried to introduce our own C/Fe culture. Your planetary and various City governments co-operated with us because it was expedient to do so. Still, in twenty-five years, we have failed. The harder we tried, the stronger the opposing party of the Medievalists grew."

"I know all this," said Baley. He thought: No use. He's got to tell this in his own way, like a field recording. He yelled silently at R. Daneel: Machine!

R. Daneel went on, "It was Dr. Sarton who first theorized that we must reverse our tactics. We must first find a segment of Earth's population that desired what we desired or could be persuaded to do so. By encouraging and helping them, we could make the movement a native one rather than a foreign one. The difficulty was in finding the native element best suited for our purposes. You, yourself, Elijah, were an interesting experiment."

"I? I? What do you mean?" demanded Baley.

"We were glad your Commissioner recommended you. From your psychic profile we judged you to be a useful specimen. Cerebroanalysis, a process I conducted upon you as soon as I met you, confirmed our judgment. You are a practical man, Elijah. You do not moon romantically over Earth's past, despite your healthy interest in it. Nor do you stubbornly embrace the City culture of Earth's present day. We felt that people such as yourself were the ones that could lead Earthmen to the stars once more. It was one reason Dr. Fastolfe was anxious to see you yesterday morning.

"To be sure, your practical nature was embarrassingly intense. You refused to understand that the fanatical service of an ideal, even a mistaken ideal, could make a man do things quite beyond his ordinary capacity, as, for instance, crossing open country at night to destroy someone he considered an archenemy of his cause. We were not overly surprised, therefore, that you were stubborn enough and daring enough to attempt to prove the murder a fraud. In a way, it proved you were the man we wanted for our experiment."

"For God's sake, what experiment?" Baley brought his fist down on the table.

"The experiment of persuading you that colonization was the answer to Earth's problems."

"Well, I was persuaded. I'll grant you that."

"Yes, under the influence of the appropriate drug."

Baley's teeth loosened their grip on his pipestem. He caught the pipe as it fell. Once again, he was seeing that scene in the Spacetown dome. Himself swimming back to awareness after the shock of learning that R. Daneel was a robot after all; R. Daneel's smooth fingers pinching up the flesh of his arm; a hypo-shiver standing out darkly under his skin and then fading away.

He said, chokingly, "What was in the hypo-shiver?"

"Nothing that need alarm you, Elijah. It was a mild drug intended only to make your mind more receptive."

"And so I believed whatever was told me. Is that it?"

"Not quite. You would not believe anything that was foreign to the basic pattern of your thought. In fact, the results of the experiment were disappointing. Dr. Fastolfe had hoped you would become fanatical and single-minded on the subject. Instead you became rather distantly approving, no more. Your practical nature stood in the way of anything further. It made us realize that our only hope was the romantics after all, and the romantics, unfortunately, were all Medievalists, actual or potential."

Baley felt incongruously proud of himself, glad of his stubbornness, and happy that he had disappointed them. Let them experiment with someone else.

He grinned savagely. "And so now you've given up and are going home?"

"Why, that is not it. I said a few moments ago that we were satisfied Earth would colonize. It was you that gave us the answer."

"I gave it to you? How?"

"You spoke to Francis Clousarr of the advantages of colonization. You spoke rather fervently, I judge. At least our experiment on you had that result. And Clousarr's cerebroanalytic properties changed. Very subtly, to be sure, but they changed."

"You mean I convinced him that I was right? I don't believe that."

"No, conviction does not come that easily. But the cerebroanalytic changes demonstrated conclusively that the Medievalist mind is open to that sort of conviction. I experimented further myself. When leaving Yeast-town, guessing what might have happened between you two from his cerebric changes, I made the proposition of a school for emigrants as a way of insuring his children's future. He rejected that, but again his aura changed, and it seemed to me quite obvious that it was the proper method of attack."

R. Daneel paused, then spoke on.

"The thing called Medievalism shows a craving for pioneering. To be sure, the direction in which that craving turns itself is toward Earth itself, which is near and which has the precedent of a great past. But the vision of worlds beyond is a similar something and the romantic can turn to it easily, just as Clousarr felt the attraction as a result of one lecture from you.

"So you see, we of Spacetown had already succeeded without knowing it. We ourselves, rather than anything we tried to introduce, were the unsettling factor. We crystallized the romantic impulses on Earth into Medievalism and induced an organization in them. After all, it is the Medievalist who wishes to break the cake of custom, not the City officials who have most to gain from preserving the status quo. If we leave Spacetown now, if we do not irritate the Medievalist by our continued presence until he has committed himself to Earth, and only Earth, past redemption, if we leave behind a few obscure individuals or robots such as myself who, together with sympathetic Earthmen such as yourself, can establish the training schools for emigrants that I spoke of, the Medievalist will eventually turn away from Earth. He will need robots and will either get them from us or build his own. He will develop a C/Fe culture to suit himself."

It was a long speech for R. Daneel. He must have realized that himself, for, after another pause, he said, "I tell you all this to explain why it is necessary to do something that may hurt you."

Baley thought bitterly: A robot must not hurt a human being, unless he can think of a way to prove it is for the human being's ultimate good after all.

Baley said, "Just a minute. Let me introduce a practical note. You'll go back to your worlds and say that an Earthman killed a Spacer and is unpunished. The Outer Worlds will demand an indemnity from Earth, and I warn you, Earth is no longer in a mood to endure such treatment. There will be trouble."

"I am sure that will not happen, Elijah. The elements on our planets that would be most interested in pressing for an indemnity would be also most interested in forcing an end to Spacetown. We can easily offer the latter as an inducement to abandon the former. It is what we plan to do, anyway. Earth will be left in peace."

And Baley broke out, his voice hoarse with sudden despair, "And where does that leave me? The Commissioner will drop the Sarton investigation at once if Spacetown is willing, but the R. Sammy thing will have to continue, since it points to corruption inside the Department. He'll be in any minute with a ream of evidence against me. I know that. It's been arranged. I'll be declassified, Daneel. There's Jessie to consider. She'll be smeared as a criminal. There's Bentley - "

R. Daneel said, "You must not think, Elijah, that I do not understand the position in which you find yourself. In the service of humanity's good, the minor wrongs must be tolerated. Dr. Sarton has a surviving wife, two children, parents, a sister, many friends. All must grieve at his death and be saddened at the thought that his murderer has not been found and punished."

"Then why not stay and find him?"

"It is no longer necessary."

Baley said, bitterly, "Why not admit that the entire investigation was an excuse to study us under field conditions? You never gave a damn who killed Dr. Sarton."

"We would have liked to know," said R. Daneel, coolly, "but we were never under any delusions as to which was more important, an individual or humanity. To continue the investigation now would involve interfering with a situation which we now find satisfactory. We could not foretell what damage we might do."

"You mean the murderer might turn out to be a prominent Medievalist and right now the Spacers don't want to do anything to antagonize their new friends."

"It is not as I would say it, but there is truth in your words."

"Where's your justice circuit, Daneel? Is this justice?"

"There are degrees of justice, Elijah. When the lesser is incompatible with the greater, the lesser must give way."

It was as though Baley's mind were circling the impregnable logic of R. Daneel's positronic brain, searching for a loophole, a weakness.

He said, "Have you no personal curiosity, Daneel? You've called yourself a detective. Do you know what that implies? Do you understand that an investigation is more than a job of work? It is a challenge. Your mind is pitted against that of the criminal. It is a clash of intellect. Can you abandon the battle and admit defeat?"

"If no worthy end is served by a continuation, certainly."

"Would you feel no loss? No wonder? Would there be no little speck of dissatisfaction? Frustrated curiosity?"

Baley's hopes, not strong in the first place, weakened as he spoke. The word "curiosity," second time repeated, brought back his own remarks to Francis Clousarr four hours before. He had known well enough then the qualities that marked off a man from a machine. Curiosity had to be one of them. A six-week-old kitten was curious, but how could there be a curious machine, be it ever so humanoid?

R. Daneel echoed those thoughts by saying, "What do you mean by curiosity?"

Baley put the best face on it. "Curiosity is the name we give to a desire to extend one's knowledge."

"Such a desire exists within me, when the extension of knowledge is necessary for the performance of an assigned task."

"Yes," said Baley, sarcastically, "as when you ask questions about Bentley's contact lenses in order to learn more of Earth's peculiar customs."

"Precisely," said R. Daneel, with no sign of any awareness of sarcasm. "Aimless extension of knowledge, however, which is what I think you really mean by the term curiosity, is merely inefficiency. I am designed to avoid inefficiency."

It was in that way that the "sentence" he had been waiting for came to Elijah Baley, and the opaque jelly shuddered and settled and changed into luminous transparency.

While R. Daneel spoke, Baley's mouth opened and stayed so.

It could not all have burst full-grown into his mind. Things did not work so. Somewhere, deep inside his unconscious, he had built a case, built it carefully and in detail, but had been brought up short by a single inconsistency. One inconsistency that could be neither jumped over, burrowed under, nor shunted aside. While that inconsistency existed, the case remained buried below his thoughts, beyond the reach of his conscious probing.

But the sentence had come; the inconsistency had vanished; the case was his.

The glare of mental light appeared to have stimulated Baley mightily. At least he suddenly knew what R. Daneel's weakness must be, the weakness of any thinking machine. He thought feverishly, hopefully: The thing must be literal-minded.

He said, "Then Project Spacetown is concluded as of today and with it the Sarton investigation. Is that it?"

"That is the decision of our people at Spacetown," agreed R. Daneel, calmly.

"But today is not yet over." Baley looked at his watch. It was 22:30. "There is an hour and a half until midnight."

R. Daneel said nothing. He seemed to consider.

Baley spoke rapidly. "Until midnight, the project continues then. You are my partner and the investigation continues." He was becoming almost telegraphic in his haste. "Let us go on as before. Let me work. It will do your people no harm. It will do them great good. My word upon it. If, in your judgment, I am doing harm, stop me. It is only an hour and a half I ask."

R. Daneel said, "What you say is correct. Today is not over. I had not thought of that, partner Elijah."

Baley was "partner Elijah" again.

He grinned, and said, "Didn't Dr. Fastolfe mention a film of the scene of the murder when I was in Spacetown?"

"He did," said R. Daneel.

Baley said, "Can you get a copy of the film?"

"Yes, partner Elijah."

"I mean now! Instantly!"

"In ten minutes, if I can use the Department transmitter."

The process took less time than that. Baley stared at the small aluminum block he held in his trembling hands. Within it the subtle forces transmitted from Spacetown had strongly fixed a certain atomic pattern.

And at that moment, Commissioner Julius Enderby stood in the doorway. He saw Baley and a certain anxiety passed from his round face, leaving behind it a look of growing thunder.

He said, uncertainly, "Look here, Lije, you're taking a devil of a time, eating."

"I was bone-tired, Commissioner. Sorry if I've delayed you."

"I wouldn't mind, but... You'd better come to my office." Baley's eyes flicked toward R. Daneel, but met no answering look. Together they moved out of the lunchroom.

Julius Enderby tramped the floor before his desk, up and down, up and down. Baley watched him, himself far from composed. Occasionally, he glanced at his watch.

22:45.

The Commissioner moved his glasses up onto his forehead and rubbed his eyes with thumb and forefinger. He left red splotches in the flesh around them, then restored the glasses to their place, blinking at Baley from behind them.

"Lije," he said suddenly, "when were you last in the Williamsburg power plant?"

Baley said, "Yesterday, after I left the office. I should judge at about eighteen or shortly thereafter."

The Commissioner shook his head. "Why didn't you say so?"

"I was going to. I haven't given an official statement yet."

"What were you doing there?"

"Just passing through on my way to our temporary sleeping quarters."

The Commissioner stopped short, standing before Baley, and said, "That's no good, Lije. No one just passes through a power plant to get somewhere else."

Baley shrugged. There was no point in going through the story of the pursuing Medievalists, of the dash along the strips. Not now.

He said, "If you're trying to hint that I had an opportunity to get the alpha-sprayer that knocked out R. Sammy, I'll remind you that Daneel was with me and will testify that I went right through the plant without stopping and that I had no alpha-sprayer on me when I left."

Slowly, the Commissioner sat down. He did not look in R. Daneel's direction or offer to speak to him. He put his pudgy white hands on the desk before him and regarded them with a look of acute misery on his face.

He said, "Lije, I don't know what to say or what to think. And it's no use having your - your partner as alibi. He can't give evidence."

"I still deny that I took an alpha-sprayer."

The Commissioner's fingers intertwined and writhed. He said, "Lije, why did Jessie come to see you here this afternoon?"

"You asked me that before, Commissioner. Same answer. Family matters."

"I've got information from Francis Clousarr, Lije."

"What kind of information?"

"He claims that a Jezebel Baley is a member of a Medievalist society dedicated to the overthrow of the government by force."

"Are you sure he has the right person? There are many Baleys."

"There aren't many Jezebel Baleys."

"He used her name, did he?"

"He said Jezebel. I heard him, Lije. I'm not giving you a second-hand report."

"All right. Jessie was a member of a harmless lunatic-fringe organization. She never did anything but attend meetings and feel devilish about it."

"It won't look that way to a board of review, Lije."

"You mean I'm going to be suspended and held on suspicion of destroying government property in the form of R. Sammy?"

"I hope not, Lije, but it looks awfully bad. Everyone knows you didn't like R. Sammy. Your wife was seen talking to him this afternoon. She was in tears and some of her words were heard. They were harmless in themselves, but two and two can be added up, Lije. You might feel it was dangerous to leave him in a position to talk. And you had an opportunity to obtain the weapon."

Baley interrupted. "If I were wiping out all evidence against Jessie, would I bring in Francis Clousarr? He seems to know a lot more about her than R. Sammy could have. Another thing. I passed through the power plant eighteen hours before R. Sammy spoke to Jessie. Did I know that long in advance that I would have to destroy him and pick up an alpha-sprayer out of clairvoyance?"

The Commissioner said, "Those are good points. I'll do my best. I'm sorry about this, Lije."

"Yes? Do you really believe I didn't do it, Commissioner?"

Enderby said slowly, "I don't know what to think, Lije. I'll be frank with you."

"Then I'll tell you what to think. Commissioner, this is all a careful and elaborate frame."

The Commissioner stiffened. "Now, wait, Lije. Don't strike out blindly. You won't get any sympathy with that line of defense. It's been used by too many bad eggs."

"I'm not after sympathy. I'm just telling the truth. I'm being taken out of circulation to prevent me from learning the facts about the Sarton murder. Unfortunately for my framing pal, it's too late for that."

"What!"

Baley looked at his watch. It was 23:00.

He said, "I know who is framing me, and I know how Dr. Sarton was killed and by whom, and I have one hour to tell you about it, catch the man, and end the investigation."